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authorDavid P. Quigley <dpquigl@tycho.nsa.gov>2009-09-09 14:25:37 -0400
committerJames Morris <jmorris@namei.org>2009-09-10 10:11:29 +1000
commitddd29ec6597125c830f7badb608a86c98b936b64 (patch)
treee6df1ef9a635179de78650d006ecb4cd1453ebb1 /fs/sysfs/inode.c
parent1ee65e37e904b959c24404139f5752edc66319d5 (diff)
sysfs: Add labeling support for sysfs
This patch adds a setxattr handler to the file, directory, and symlink inode_operations structures for sysfs. The patch uses hooks introduced in the previous patch to handle the getting and setting of security information for the sysfs inodes. As was suggested by Eric Biederman the struct iattr in the sysfs_dirent structure has been replaced by a structure which contains the iattr, secdata and secdata length to allow the changes to persist in the event that the inode representing the sysfs_dirent is evicted. Because sysfs only stores this information when a change is made all the optional data is moved into one dynamically allocated field. This patch addresses an issue where SELinux was denying virtd access to the PCI configuration entries in sysfs. The lack of setxattr handlers for sysfs required that a single label be assigned to all entries in sysfs. Granting virtd access to every entry in sysfs is not an acceptable solution so fine grained labeling of sysfs is required such that individual entries can be labeled appropriately. [sds: Fixed compile-time warnings, coding style, and setting of inode security init flags.] Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov> Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'fs/sysfs/inode.c')
-rw-r--r--fs/sysfs/inode.c134
1 files changed, 98 insertions, 36 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 555f0ff988d..2b6a8d9de73 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -18,6 +18,8 @@
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/sched.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
#include "sysfs.h"
extern struct super_block * sysfs_sb;
@@ -35,6 +37,7 @@ static struct backing_dev_info sysfs_backing_dev_info = {
static const struct inode_operations sysfs_inode_operations ={
.setattr = sysfs_setattr,
+ .setxattr = sysfs_setxattr,
};
int __init sysfs_inode_init(void)
@@ -42,18 +45,37 @@ int __init sysfs_inode_init(void)
return bdi_init(&sysfs_backing_dev_info);
}
+struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
+{
+ struct sysfs_inode_attrs *attrs;
+ struct iattr *iattrs;
+
+ attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
+ if (!attrs)
+ return NULL;
+ iattrs = &attrs->ia_iattr;
+
+ /* assign default attributes */
+ iattrs->ia_mode = sd->s_mode;
+ iattrs->ia_uid = 0;
+ iattrs->ia_gid = 0;
+ iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
+
+ return attrs;
+}
int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
struct inode * inode = dentry->d_inode;
struct sysfs_dirent * sd = dentry->d_fsdata;
- struct iattr * sd_iattr;
+ struct sysfs_inode_attrs *sd_attrs;
+ struct iattr *iattrs;
unsigned int ia_valid = iattr->ia_valid;
int error;
if (!sd)
return -EINVAL;
- sd_iattr = sd->s_iattr;
+ sd_attrs = sd->s_iattr;
error = inode_change_ok(inode, iattr);
if (error)
@@ -65,42 +87,77 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
if (error)
return error;
- if (!sd_iattr) {
+ if (!sd_attrs) {
/* setting attributes for the first time, allocate now */
- sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
- if (!sd_iattr)
+ sd_attrs = sysfs_init_inode_attrs(sd);
+ if (!sd_attrs)
return -ENOMEM;
- /* assign default attributes */
- sd_iattr->ia_mode = sd->s_mode;
- sd_iattr->ia_uid = 0;
- sd_iattr->ia_gid = 0;
- sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
- sd->s_iattr = sd_iattr;
+ sd->s_iattr = sd_attrs;
+ } else {
+ /* attributes were changed at least once in past */
+ iattrs = &sd_attrs->ia_iattr;
+
+ if (ia_valid & ATTR_UID)
+ iattrs->ia_uid = iattr->ia_uid;
+ if (ia_valid & ATTR_GID)
+ iattrs->ia_gid = iattr->ia_gid;
+ if (ia_valid & ATTR_ATIME)
+ iattrs->ia_atime = timespec_trunc(iattr->ia_atime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_MTIME)
+ iattrs->ia_mtime = timespec_trunc(iattr->ia_mtime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_CTIME)
+ iattrs->ia_ctime = timespec_trunc(iattr->ia_ctime,
+ inode->i_sb->s_time_gran);
+ if (ia_valid & ATTR_MODE) {
+ umode_t mode = iattr->ia_mode;
+
+ if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
+ mode &= ~S_ISGID;
+ iattrs->ia_mode = sd->s_mode = mode;
+ }
}
+ return error;
+}
- /* attributes were changed atleast once in past */
-
- if (ia_valid & ATTR_UID)
- sd_iattr->ia_uid = iattr->ia_uid;
- if (ia_valid & ATTR_GID)
- sd_iattr->ia_gid = iattr->ia_gid;
- if (ia_valid & ATTR_ATIME)
- sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
- inode->i_sb->s_time_gran);
- if (ia_valid & ATTR_MTIME)
- sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
- inode->i_sb->s_time_gran);
- if (ia_valid & ATTR_CTIME)
- sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
- inode->i_sb->s_time_gran);
- if (ia_valid & ATTR_MODE) {
- umode_t mode = iattr->ia_mode;
-
- if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
- mode &= ~S_ISGID;
- sd_iattr->ia_mode = sd->s_mode = mode;
- }
+int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+ size_t size, int flags)
+{
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ struct sysfs_inode_attrs *iattrs;
+ void *secdata;
+ int error;
+ u32 secdata_len = 0;
+
+ if (!sd)
+ return -EINVAL;
+ if (!sd->s_iattr)
+ sd->s_iattr = sysfs_init_inode_attrs(sd);
+ if (!sd->s_iattr)
+ return -ENOMEM;
+
+ iattrs = sd->s_iattr;
+
+ if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
+ const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+ error = security_inode_setsecurity(dentry->d_inode, suffix,
+ value, size, flags);
+ if (error)
+ goto out;
+ error = security_inode_getsecctx(dentry->d_inode,
+ &secdata, &secdata_len);
+ if (error)
+ goto out;
+ if (iattrs->ia_secdata)
+ security_release_secctx(iattrs->ia_secdata,
+ iattrs->ia_secdata_len);
+ iattrs->ia_secdata = secdata;
+ iattrs->ia_secdata_len = secdata_len;
+ } else
+ return -EINVAL;
+out:
return error;
}
@@ -146,6 +203,7 @@ static int sysfs_count_nlink(struct sysfs_dirent *sd)
static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
{
struct bin_attribute *bin_attr;
+ struct sysfs_inode_attrs *iattrs;
inode->i_private = sysfs_get(sd);
inode->i_mapping->a_ops = &sysfs_aops;
@@ -154,16 +212,20 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
inode->i_ino = sd->s_ino;
lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
- if (sd->s_iattr) {
+ iattrs = sd->s_iattr;
+ if (iattrs) {
/* sysfs_dirent has non-default attributes
* get them for the new inode from persistent copy
* in sysfs_dirent
*/
- set_inode_attr(inode, sd->s_iattr);
+ set_inode_attr(inode, &iattrs->ia_iattr);
+ if (iattrs->ia_secdata)
+ security_inode_notifysecctx(inode,
+ iattrs->ia_secdata,
+ iattrs->ia_secdata_len);
} else
set_default_inode_attr(inode, sd->s_mode);
-
/* initialize inode according to type */
switch (sysfs_type(sd)) {
case SYSFS_DIR: